Automatic power control (APC) of light emitting devices allows for a constant and a consistent output from these devices. Generally, automatic power control of edge emitting laser devices is easily achieved because edge emitting devices emit light from two ends. Thus, enabling one of the light emitting ends to be used to measure the power output, which is subsequently used to adjust the power input to the edge emitting device, thereby adjusting the power output of the edge emitting device.
However, automatic power control of a vertical cavity surface emitting laser (VCSEL) is a difficult task because the VCSEL generally emits light from only a single surface, thus making measurement of the output and subsequent adjustment thereof a difficult task. Conventionally, in order to accomplish this task, several optical devices, such as photodiodes, mirrors, beam splitters, and the like are positioned manually in the optical path of the emission from the VCSEL. With the optical devices being positioned manually, several problems or disadvantages result, such as a high cost of manufacture, a lack of repeatability, and poor quality control, and the like, thus prohibiting high volume manufacturing.
It can be readily seen that conventional APC of VCSELs has several disadvantages and problems, thus hindering their manufacture in volume manufacturing applications. Therefore, an integrated article and method for making same that simplifies the fabrication process, reduces cost, and improves reliability would be highly desirable.
It is a purpose of the present invention to provide a new and improved VCSEL with an integrated photodetector for automatic power control.
It is another purpose of the present invention to provide a new and improved VCSEL with an integrated photodetector for automatic power control which is cost effective and has improved efficiency.